This invention relates to a lock or lock mechanism designed for mortise mounting in a door frame, stile, or jamb. The invention more particularly concerns what is referred to herein as a security lock, such as might be used in detention facilities and industrial applications, and includes means for unlocking the lock produced either directly by mechanical action or by remotely controlled means.
The specific and preferred embodiment of the lock herein disclosed is designed for mounting in a narrow-style, jamb or casing structure. The lock includes a mechanical system for deadlocking a latch bolt in the lock in an extended position and with the lock securing a door in a closed position. Unlocking of the lock may be performed mechanically, as with a key actuating a standard mortise key cylinder, and remotely, more specifically by actuating a pneumatically operated device which is operable to produce unlocking of the lock.
So called security locks are known, and exemplary of such are those disclosed in U.S. Pat. Nos. 1,569,228, 2,032,765, 2,800,347, 3,999,411, and 4,237,711. Generally, these prior art devices may be characterized as including a complicated linkage and lever system for producing the unlocking features desired. This has tended to increase the overall size of the mechanism if a rugged, sturdy construction is to be obtained. Most have relied upon an electrically operated solenoid for producing remote unlocking, which is disadvantageous as there is heat build up in a solenoid with the solenoid energized over a long period of time, and solenoids generally are inefficient (without a linkage multiplier) in effecting any long throw, as is desirable in producing multiple locking functions in a lock. Locks which rely on nonmechanical means, such as a fluid or air system for maintaining a deadlocked condition, have the disadvantage in that the deadlocking feature is lost with interruption of the system by which deadlocking is achieved.
A general object of this invention is to provide a lock advantageously employed as a security lock in detention and other facilities, with improved means for either mechanically or remotely effecting unlocking of the lock.
Another object is to provide such a lock mechanism with an improved construction for producing deadlocking of the latch bolt thus preventing the bolt from being retracted using tools or other unauthorized devices.
Another object is to provide a lock mechanism suitable for use in security applications featuring pneumatic means for producing unlocking and, as a corollary, a lock which features a mechanical system for producing deadlocking of the latch bolt without reliance on the pneumatic system.
A preferred and more specific object of the invention is to provide a security lock which includes a pivoted latch bolt movable between locking and unlocking positions, and simplified mechanism including a slidable actuator and a limited number of other parts for shifting the latch bolt to an unlocked state, for producing deadlocking, and other functions.
In a preferred embodiment of the invention, the lock features an elongate, double-section housing portion which encloses operating parts and which mounts a pivoted latch bolt and a door-position sensor, both of which are extensible and retractable relative to the housing. A spring biased, elongate, slidable actuator within the housing is shiftable along its length to produce retraction of the latch bolt and deadlocking of the latch bolt, deadlocking being under the control also of the door-position sensor. The actuator is movable either mechanically, as with a key, or by operation of a pneumatic device, more specifically, an air-operated piston cylinder. With the air-operated piston cylinder removed, as for repair or replacement purposes, mechanical operation of the lock is unimpaired.